In the press release, Cambio Radical asked Santos to include some of Vargas Lleras’ proposals for government in his platform, including those on housing, taxation reform, international relations and telecommunications.
Senators Alfonso Valdivieso and Rodrigo Lara, who had expressed their opposition to the alliance, did not comment on the decision.
Vargas Lleras won 10.13% of the vote in the first round of Colombia’s presidential elections on May 30.
Santos won the round with 46.57% of the vote, while his main contender, Green Party candidate Antanas Mockus, won 21.47%.
As no candidate achieved the majority vote required to win the first round outright, Mockus and Santos will face-off in second round election scheduled for June 20.